title: Zinc complexes supported by methyl salicylato ligands: synthesis, structure, and application in ring-opening polymerization of L-lactide.
abstract: Two novel zinc alkoxides supported by chelating methyl salicylato (MesalO; MesalOH = methyl salicylate) ligands were successfully synthesized and characterized. Reaction of MesalOH with ZnEt2 (2:1) gives a tetranuclear cluster [Zn(MesalO)2]4 (1), which by addition of pyridine is transformed to the mononuclear compound [Zn(MesalO)2(py)2] (2). Compounds 1 and 2 were characterized by elemental analysis, NMR, IR, and single crystal X-ray diffraction. The catalytic activity of both compounds was tested for the ring-opening polymerization (ROP) of L-lactide (L-LA). It was found that compounds 1 and 2 are efficient initiators of the ROP of L-LA, yielding cyclic PLLA with weight average molecular weights up to 100 kDa for 2. The treatment of 2 with 1 equiv. of BnOH in toluene afforded a dimeric compound [Zn(OBn)(MesalO)(py)]2 (3). The addition of L-LA to a combination of 1 and 4 equiv. of BnOH in THF or 2 and 1 equiv. of BnOH in toluene led to the rapid and efficient generation of PLLA with end-capped BnO groups.
authors.affiliation: Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland. piotr.sobota@chem.uni.wroc.pl.
authors.forename: Rafał
authors.initials: R
authors.lastname: Petrus
authors.forename: Piotr
authors.initials: P
authors.lastname: Sobota
mesh_terms: D002384:Catalysis; D018360:Crystallography, X-Ray; D004146:Dioxanes / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D011091:Polyesters / Q000138:chemical synthesis* / Q000737:chemistry; D058105:Polymerization; D011725:Pyridines / Q000138:chemical synthesis* / Q000737:chemistry; D012459:Salicylates / Q000138:chemical synthesis* / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D013055:Spectrophotometry, Infrared; D015032:Zinc / Q000737:chemistry*
chemical_list: D004146:Dioxanes; D009942:Organometallic Compounds; D011091:Polyesters; D011725:Pyridines; D012459:Salicylates; C033616:poly(lactide); C091880:dilactide; D015032:Zinc